Ring and traveler

ABSTRACT

Thread guiding device for ring spinning and ring twisting frames includes a ring having a radially inner engagement surface and a bottom engagement surface, and an ear-shaped traveller mounted on the ring for traveling around the same, the traveller being in engagement only with the inner and bottom engagement surfaces of the ring in the course of travel thereof about the ring.

United States Patent 1 First, deceased et al.

[54] RING AND TRAVELER [76] Inventors: Stefan Fiirst, deceased, late of Monchengladbach, Germany; by Stefanie Dormanns, 43 Industriestrasse, Wegberg; by Hans Fiirst, 28 Ludwig-Weber-Strasse, Monchengladbach, both of Germany heirs and legal representatives [22] Filed: Oct. 19, 1970 [21] Appl. No.: 81,773

[30] Foreign Application Priority Data Oct. 18, 1969 Germany P 19 52 570.3 Nov. 15,1969 Germany P 19 57 552.1

[52] US. Cl. 57/120, 57/120 [51] Int. Cl D0lh 7/62 [58] Field of Search 57/119-125 [56] References Cited UNITED STATES PATENTS 1,984,779 12/1934 Wentworth 57/1 25 1,998,973 4/1935 Stuart 57/120 Dec. 11, 1973 2,102,861 12/1937 Stuart 57/120 2,433,580 12/1947 Stuart 57/119 2,831,313 4/1958 Burns et al 57/119 2,905,269 9/1959 Mulholland... 57/120 X 2,206,591 7/1940 Wentworth 57/119 2,335,121 11/1943 Jerome 57/125 3,157,981 11/1964 Wayson 57/125 3,318,081 5/1967 Wayson et a1. 57/125 2,448,150 8/1948 Mulholland 57/119 2,756,558 7/1956 Camp et al. 57/119 3,226,924 1/1966 Dalpiaz 1 57/125 3,332,225 7/1967 Drisch et a1. 57/125 3,362,152 1/1968 Machie 57/125 Primary Examiner-John Petrakes Att0rneyCurt M. Avery, Arthur E. Wilfond, Herbert L. Lerner and Daniel J. Tick [57] ABSTRACT Thread guiding device for ring spinning and ring twisting frames includes a ring having a radially inner engagement surface and a bottom engagement surface, and an ear-shaped traveller mounted on the ring for traveling around the same, the traveller being in engagement only with the inner and bottom engagement surfaces of the ring in the course of travel thereof about the ring. I

13 Claims, 3 Drawing, Figures PATENTED DEC 1 1 I975 SHEET 1 0F 2 PATENTED 1 1 I975 SHEET 2 (1F 2 RING AND TRAVELER The invention relates to a thread guiding device for ring spinning and ring twisting frames.

Such thread guiding devices for ring spinning and ring twisting frames are formed generally from socalled flange rings with C-shaped or elliptical travellers that are mounted thereon. They are preferably used for spinning and for fine twisting. A disadvantage of these thread guiding devices, however, is that the speed of travel of the traveller cannot exceed a predetermined maximum because of unfavorable lubrication conditions. Numerous attempts to increase the traveller speed by varying the mutual engagement surfaces of the ring and the traveller have not had any salutary results.

It is accordingly an object of the invention to provide thread guiding device for ring spinning and ring twisting which permits a marked increase in the travel velocity of the traveller on the ring of the thread guiding device. With the foregoing and other objects in view there is provided a thread guiding device for ring spinning and ring twisting frames comprising a ring having a radially inner engagement surface and a bottom engagement surface, and an ear-shaped traveller mounted on the ring for travelling around the same, the traveller being in engagement only with the inner and bottom engagement surfaces of the ring in the course of travel thereof about the ring.

Rings with ear-shaped ring travellers are, in fact, known, having been used essentially only for twisting. These ear-shaped ring travellers do not however engage the ring only at the radially inner surface thereof but rather, due to the inclined position of the traveller caused by the thread path or pull, also engage the underside and the upper side of the ring. The thread or yarn accordingly runs either through a pocket formed in the ring traveller, or the ring is provided with a recess which affords the yarn or thread space for an adequate passing therethrough. In contrast to these known thread guiding devices with ear-shaped ring travellers, in the thread guiding deviceaccording to the invention of the instant application the ring traveller does not engage the ring at the upper side or surface thereof, so that features such as the provision of a pocket in the ring traveller or a recess in the ring are dispensed with. Adequate space for passage therethrough of the yarn or thread is provided between the ring traveller and the upper surface of the ring in accordance with the invention, as is attained otherwise only for c-shaped travellers.

In accordance with a further advantageous feature of I the invention, the wedge-shaped volume for the lubricant formed due to the fact that the radius of curvature of the ring traveller is two to three times, preferably 2.5 times, the radius of curvature of the ring. Naturally, only the radius of curvature of the traveller and of the ring in the vicinity of the uppermost limit of contact between the ring and the ring traveller, i.e. in the vicinity of the zone at which the thread being processed is passed through the traveller is of significance.

The forces exerted on the ear-shaped ring traveller do not only force the traveller against the radially inner surface of the ring but also apply considerable pressure of the foot of the traveller against theunderside or bottom surface of the ring. In order to reduce the force of application to the bottom surface of the ring, in accordance with yetanother feature of the invention, the radially inner surface of the ring engaged by the ring traveller, in addition to the curvature thereof, has an inclination to the horizontal of from 4-14, preferably 10, in the sense of an increase of diameter in a downward direction. In this manner, a considerable portion of the upwardly directed tension components of the ring traveller that originate from the thread path or pull is compensated, as is more fully explained hereinafter with regard to the description of the illustrated embodiments.

In accordance with an additional feature of the invention, a lubrication supply device is connected to the surface of the ring engaged by the traveller. Thereby, the resultant embodiment of the invention is employable not only with C-shaped travellers, i.e. for spinning and fine twisting but can also be employed in a situation wherein heretofore the ear-shaped travellers have been exclusively used. As compared to the heretofore known rings with ear-shaped ring travellers which not only engage the ring at the radially inner and bottom surface thereof, but also at the upper surface thereof,

the thread guiding device according to the invention of the instant application presents the marked advantage that the traveller can no longer ride with its edge on the ring, which considerably increases the longevity or durability thereof, and fiber fly forming between the ring traveller and the upper surface of the ring is driven off to the outside. In this manner, advantages have been obtained for the ocnventional rings with ear-shaped ring travellers when employing the invention of the in stant application which were obtainable heretofore only with difficulty or were not attainable at all with the varied types of special construction.

In accordance with yet another feature of the invention, the lubrication supplying device for the surface of the ring engaged by the traveller is formed of lubricant supply lines and grooves for the ring. It is also possible, in accordance with the invention, to make the ring of a porous material which has been found to be especially suitable for the use of ring travellers, the ring travellers being formed at least at the engaging surfaces thereof of plastic material.

In accordance with an added feature of the thread guiding device of the invention, there is provided a ring for ear-shaped travellers wherein the total height of the ring is at most 10 mm, and wherein the surfaces thereof engageable with the traveller continuously merge into the upper surface of the ring. Such a ring for earshaped travellers differs from the heretofore known rings for ear-shaped travellers by the fact that it has a relatively small total height and by the fact that no recess is provided therein for passage of yarn or thread therethrough.

In accordance with still another feature of the invention, there is provided a thread guiding device wherein the surface of the ring engaging; the traveller merges with the upper surface of the ring with an initial radius of curvature that is from one-fifth t0 one-tenth the height of the ring. Thereby, on the one hand, clamping of the yarn or thread between the ring and the ring traveller is avoided while, on the other hand, a sufficiently large wedge-shaped volume is produced between the ring and the ring traveller which facilitates penetration into the same of grease and fiber particles for lubricating purposes, when the thread guiding device of the invention, for example, is employed for spinning or fine twisting without a lubrication supply device.

In order to ensure that the just-mentioned ring employed in a thread guiding device according to the invention affords, even under especially undesirable conditions, a reliable guidance of the ear-shaped ring traveller which does not engage the ring at the upper surface thereof, there is further provided in accordance with the invention a holder for the ring whose height or thickness is smaller than one-third the height of the ring. In this regard, it should be understood that by a ring holder there is meant every means which serves for holding the ring between both ends of the traveller, i.e., also, for example, besides the well-known ring crosspieces also, for example, the ring bank, if the ring is directly inserted into the ring bank.

In accordance with a concomitant feature of the thread guiding device of the invention, the ear-shaped ring traveller is provided with an upper large and a lower small hook-shaped portion, respectively, which together surround the ring, the inner height of the traveller being 12 mm at maximum and the large hookshaped portion thereof being curved in one direction. In this manner, the ear-shaped ring traveller of the invention distinguishes from heretofore known earshaped ring travellers, on the one hand, by its relatively small size and, on the other hand, by the omission of a pocket therein, which affords passage therethrough of yarn or thread in the heretofore known ear-shaped ring travellers.

In accordance with still another feature of the invention, and in order to provide especially desirable travel characteristics, the large hook-shaped portion of the traveller has a length which-is substantially double that of the smaller hook-shaped portion. Moreover, it is another feature of the invention to construct the larger hook-shaped portion with an inner width which is at least 1.2 times the inner width of the smaller hookshaped portion. Furthermore, in accordance with an added feature of the invention, the spacing of the ends of the ear-shaped ring traveller corresponds substantially to half the inner height of the traveller.

If at least the end of the larger hook-shaped portion of the traveller is directed outwardly in accordance with a further feature of the invention, the produced fiber fly and dust which is unnecesaary for lubrication can escape without hindrance. In the heretofore known ear-shaped ring travellers, these fibers and dust particles accumulate either in the recess of the ring or in the pocket of the ring traveller because the engagement between the ring and the ring traveller at the upper surface of the ring prevents escape thereof to the outside. In order to avoid complete blockage, special dust removing means are provided at the revolving path of the ring traveller in the heretofore known devices, which is no longer necessary for a device according to the invention of the instant application.

Other features which are considered as characteristic for the invention are set forth in the appended claims.

Although the invention is illustrated and described herein as thread guiding device for ring spinning and ring twisting frames, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.

The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description when read in connection with the accompanying drawings, in which:

FIG. 1 is a sectional view of a thread guiding device according to the invention showing a ring accompanied by a traveller, only part of the ring being illustrated, the unillustrated part thereof being a mirror image of the illustrated part;

FIG. 2 is a view of the ring traveller reduced in size as seen from the inside of the ring; and

FIG. 3 is a view similar to FIG. 1 of another embodiment of a thread guiding device provided with a lubricant supplying device.

Referring now particularly to FIG. 1, there is shown a thread guiding device constructed in accordance with the invention, which is formed of a ring 1 that is secured in a ring holder or ring bank 2. An ear-shaped ring traveller 3 is rotatably mounted on the ring 1 and serves for guiding a yarn or thread F in a nonillustrated spinning cop. The ring 1 and the ear-shaped ring traveller 3 are of such dimensions that, in the course of the travel of the ring traveller 3, it engages the ring 1 only at the inner surface or side 1a and at the lower surface or side 1b thereof and not, however, as was conventional heretofore at the upper surface of side 10 thereof, so that between the upper side 10 of the ring and the ear-shaped ring traveller 3, adequate space remains for affording passage therethrough of the yarn or thread F.

In the embodiment of FIG. 1, it is clearly seen that the inner height 31 of the traveller is considerably greater than the height 1 l of the ring 1. Since the upper surface 1c of the ring 1 however can also have a different construction within the scope of the invention of the present application, for example in accordance with the illustrated dotted line shown in FIG. 1, small differences between the inner height 31 of the traveller 3 and the ring height 11a can occur. In a similar manner, this relationship can be changed by providing the upper hook-shaped portion 3b of the traveller with a different shape, for example, corresponding to the dotted line so that the traveller is provided with an inner height 31a. It is essential for the ratio of the inner height 31 of the traveller to the ring height 11 that the inner height of the traveller be generally at least 15 percent'greater than the ring height in order to permit occurring fiber fly and dust, even for conventional, inclined positions of the traveller, to pass freely to the outside so that no blockage can occur.

From FIG. 1 it can also be clearly seen that in the vicinity of the zone through which the yarn or thread passes, a downwardly narrowing wedge-shaped volume 4 filled with lubrication is disposed between the ring 1 and the ring traveller 3. Wool grease or lanolin, avivage, fiber particles and the like can penetrate from the yarn or thread passing through the space between the ring and the traveller and penetrate into this wedgeshaped volume and can serve as self-lubricating means between the ring and the traveller. It is particularly advantageous if, at the engagement surfaces between the ring 1 and the ring traveller 3, the raduis of curvature R of the ring traveller 3 is 2 to 3 times, preferably, 2.5 times as large as the radius of curvature r of the ring 1. In FIG. 1, there are also illustrated the tensile forces A and B which are exerted by the yarn or thread F on the traveller 3 in the region through which the yarn or thread passes, as well as the resultant force R. The upwardly directed tensile component A of the thread ensures a considerable engagement pressure of the small lower hook-shaped portion 3a of the traveller on the bottom surface 1b of the ring. If, however, the inner surface 1a of the ring which is engaged by the ring traveller is inclined downwardly at an angle a in the sense of an increase in the diameter, part of the tensile com ponent A of the, thread, which pulls the traveller upwardly, can be compensated by the centrifugal force Z which presses the traveller 3 against the inner surface la of the ring 1. A force which corresponds the centrifugal force Z, diminished by the value of the tensile component B of the thread, is applied to the inclined inner surface la of the ring 1. This force Z minus B pro duces a downwardly directed component C having a vertical portion C which extends opposite in direction to the upwardly directed tensile component A of the thread. If an inclination of from 4 14, preferably is selected for the angle of inclination B (F IG. 2), especially desirable friction relationships of the ring traveller 3 to the ring 1 result therefrom, because the smaller lower hook-shaped portion 3a of the ring traveller 3 engages the bottom surface lb of the ring only lightly. Consequently, the wear at this location is also reduced quite markedly.

The aforedescribed thread guiding device for ring spinning and ring twisting frames, formed of a ring and an ear-shaped ring traveller, also produces a very special effect. As aforementioned, there is provided in the vicinity of the zone through which the thread passes, a downwardly narrowing wedge-shaped volume 4 filled with lubrication, which permits penetration into the same of the wool, grease or lanolin, avivage, fiber particles or the like given off by the thread passing through the space between the ring and the'traveller can penetrate between the ring and the ring traveller. It is known that the ring traveller 3, as it is being pulled by the thread F, assumes the inclined position indicated by the angle B shown in FIG. 2, which is dependent upon the friction relationships or ratios between the ring 1 and the ring traveller 3. The angle [3, as is generally known, increases with an increase in the friction between the ring and the traveller. A largerangle [3 indicates however that the spacing between the upper surface lc of the ring and the inner surface of the upper large hookshaped portion 3b of the traveller becomes smaller. Thereby the thread F is passed through the spacing between the ring and traveller closer to the wedge-shaped volume 4 so that the lubrication is improved. The improved lubrication, however, produces raising of the ring traveller 3, i.e., a reduction in the size of the angle B. From the foregoing it can be noted that the especially advantageous position of the ring traveller 3 and the size of the angle 3 for the respective thread are automatically adjusted. This results also in an especially smooth travel of the ring traveller 3.

As mentioned hereinabove, the illustrated ring 1 exhibits marked differences as compared to the heretofore known rings for ear-shaped travellers. First of all, the total height 11 of the ring 1 should not be more than 10 mm, i.e., the ring 1 of the instant application is considerably lower in height than the heretofore known rings for ear-shaped travellers. The reason therefor is that the fiber grease between the traveler and the ring is no longer adequate when this limit is markedly exceeded. On the other hand, the height of the ring is sufficient if the thread guiding device according to the invention is employed, for example, for

spinning and fine twisting. It is furthermore clear from FIG. 1 that the ring 1 does not have any recess for the passage therethrough of the thread or yarn F. Instead of such a recess, the traveller engagement surface 1a merges into the upper surface lb of the ring with a starting radius which is one-fifth to one-fifteenth, preferably one-tenth of the ring height. This radius r in combination with a suitably shaped ring traveller permits the formation of an especially advantageous wedge-shaped volume 4 filled with lubricant.

A further feature of the new ring of the invention is that the height 12 of the ring crosspiece 1d is smaller than one-third of the ring height 1 1. Due to this feature it is assured that even for an advantageous coincidence of several limiting conditions a reliable guidance of the ear-shaped ring traveller 1, which does not engage the ring at the upper surface thereof, both during the starting up phase as well as during the regular travelling phase of the traveller. If the ring is provided with another kind of holder instead of a cross-piece M, for example, it is inserted directly into the ring bank, the given relationships are equally applicable as long as it is concerned with the region swept by the ends of the ring traveller 3.

The novel ear-shaped ring traveller of the embodiment illustrated in FIG. 1, which is used in a thread guiding device according to the invention, has a traveller with an inner height 31 of 12 mm maximum. Moreover, the upper large hook-shaped portion 3b is curved only in one direction and the ring traveller thus has no pocket for passage of thread F therethrough. Thereby, an ear-shaped ring traveller without a pocket for the passage of thread therethrough is employed for the first time, the inner height thereof being less than 12 mm. Moreover, one notes with respect to the illustrated ring traveller of the invention a special advantageous additional feature that the length 36 of the large hookshaped portion 3b is substantially twice as large as the length 32 of the small hook-shaped portion 3a. The ratio of these two hook-shaped lengths can naturally deviate by about percent from the given value in accordance with the form of the rlnG and the ring traveller.

In order to attain a trouble-free operation of the ring traveller in a thread guiding device under the most varied conditions, it is of special importance that the inner width 34 of the large hook-shaped portion be at least 1.2 times the inner width 34 of the small hook-shaped portion 3a. It is furthermore advantageous if the spacing 35 between the traveller ends comes substantially to half the inner height of the traveller. Finally it is also clearly noted with respect to the illustrated embodiment of FIG. 1 that both the large hook-shaped end 3b as well as the small hook-shaped end 30 are directed outwardly so that incident fiber fly, dust and the like can be readily ejected.

In FIG. 3, there is shown an additional embodiment constructed in accordance with the invention of the instant application. The ring 1 is formed of porous material, for example, sintered steel, the supply of lubricant being effected through lubricant supplying line 8 as well as the lubricant storage 9. Moreover, with the herein illustrated ear-shaped ring traveller the engagement surface at the ring 1' of the traveller is formed of plastic material 3c. The steel portion is completely surrounded by the plstic material only in the region of the lower traveller arc or bend 3a, whereby the steel portion over the long region can avoid contact and can have a greater elastic deformability. This relatively higher elastic deformability is of special significance for a ring traveller according to the invention of the instant application in that it permits a relatively easy mounting of the traveller on the ring.

By means of the invention, a thread guiding device for ring spinning and ring twisting frames is produced which combines the advantageous thread passage way of the C-shaped traveller with the advantageous large engagement surface of the ear-shape traveller without having to take into consideration the disadvantages of both types of travellers.

The advantageous effects of the invention are not limited to special materials for the ring or the ring traveller. It is completely possible to manufacture the ring as well as the ring traveller either of steel or a plastic material or both of steel and plastic such as, for example, the travel surface of the ring traveller on the ring can be made of plastic material such as a long-chain synthetic polymeric amide known under the trade name of nylon or the like, and the zone through which the thread passes can be formed of steel.

I claim:

1. Thread guiding device for ring spinning and ring twisitng frames comprising a ring having a radially inner surface along with a top surface and a bottom surface, an ear-shaped traveller mounted on said ring for traveling around the latter, said traveller having an intermediate portion disposed between a top portion and a bottom portion, said intermediate portion and said bottom portion engaging said radially inner surface and said bottom surface of said ring respectively in the course of travel of said traveller about said ring, said upper portion of said traveller being spaced from said top surface of said ring, said intermediate surface of said ring being generaly frusto-conical and free of openings therein, Said intermediate portion of said traveller being generally straight, said intermediate surface of said ring being joined to said top surface of said ring by an arcuate surface, said intermediate portion of said traveller being joined to said top portion of said traveller by an arcuate surface having a larger diameter than said first-mentioned arcuate surface to thereby define a lubricating wedge between said two arcuate surfaces, lubricating means disposed in said wedge, said frusto-conical surface being inclined radially outwardly and downwardly relative to the axis of said ring whereby the engagement of said interlediate portion of said traveller and the frusto-conical surface of said ring results in a downward component of force urging said ring downwardly in the course of travel of said traveller about said ring.

2. Thread guiding device according to claim 1 wherein said ring has a given height, and said top portion of said traveller has an inner vertical spacing from said ring at least percent greater than the given height of said ring.

3. The thread guiding device according to claim 2 wherein a zone is formed in the spacing between said ring and the top portion of said traveller through which a thread being processed is passed.

4. Thread guiding device according to claim 1 wherein said traveller has an arcuate upperportion extending upwardly from the uppermost engagement point thereof with said radially inner engagement surface of said ring, and said ring has an arcuate upper surface extending upwardly from said radially inner engagement surface thereof, said arcuate upper portion of said traveller having a radius of curvature substantially two or three times the radius of curvature of the arcuate upper surface of said ring.

5. Thread guiding device according to claim 1 wherein the radially inner surface of said ring engageable by said traveller, is inclined between 4 to 14 to the vertical in the sense of increasing the diameter of said ring.

6. Thread guiding device according to claim 1 wherein said ring has a total axial height of at most 10 7. Thread guiding device according to claim 1 wherein said radially inner engagement surface of said ring merges with said upper surface of said ring in a curved surface portion having a radius of curvature that is one-fifth to one-fifteenth the total axial height of the ring.

8. Thread guiding device according to claim 1 wherein said ring includes a radially outwardly extending holder portion, said holder portion having a height smaller than one-third the total axial height of the ring.

9. Thread guiding device according to claim 1 wherein said traveller is a rod-shaped member formed at opposite ends thereof with a relatively larger and a relatively smaller hook-shaped portion respectively, facing toward one another and adapted to enclose said ring, said ring traveller having a maximum inner height of 12 mm, said relatively larger hook-shaped portion being curved in only one direction.

10. Thread guiding device according to claim 9 wherein said relatively larger hook-shaped portion is substantially twice as long as said relatively smaller hook-shaped portion.

11. Thread guiding device according to claim 9 wherein said relatively larger hook-shaped portion has an internal width that is at least 1.2 times the internal width of said relatively smaller hook-shaped portion.

12. Thread guiding device according to claim 9 wherein the opposite ends of said rod-shaped member are spaced from one another a distance substantially equal to half the maximum inner height of the traveller.

13. Thread guiding device according to claim 9 wherein at least the end of said relatively larger hookshaped portion is outwardly directed.

UNITED STATES PATENT OFFICE I CERTIFICATE OF CORRECTION Patent No. 3; 777,468 Dafed December 11. 1973 fi STEFAN FfiRsT ER AL It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the headi hg to the printed specification, after line 9 insert Assignee: Reiners 8; Fiirst, M nchengladbach,

Germany- Signed and sealed this 30th day of July 19 74..

(SEAL) 1 Attest:

' I MCCOY M; GIBSON, JR, (3. MARSHALLCDANN Attesting Officer Commissioner of Patents 

1. Thread guiding device for ring spinning and ring twisitng frames comprising a ring having a radially inner surface along with a top surface and a bottom surface, an ear-shaped traveller mounted on said ring for traveling around the latter, said traveller having an intermediate portion disposed between a top portion and a bottom portion, said intermediate portion and said bottom portion engaging said radially inner surface and said bottom surface of said ring respectively in the course of travel of said traveller about said ring, said upper portion of said traveller being spaced from said top surface of said ring, said intermediate surface of said ring being general y frusto-conical and free of openings therein, Said intermediate portion of said traveller being generally straight, said intermediate surface of said ring being joined to said top surface of said ring by an arcuate surface, said intermediate portion of said traveller being joined to said top portion of said traveller by an arcuate surface having a larger diameter than said first-mentioned arcuate surface to thereby define a lubricating wedge between said two arcuate surfaces, lubricating means disposed in said wedge, said frusto-conical surface being inclined radially outwardly and downwardly relative to the axis of said ring whereby the engagement of said inter1ediate portion of said traveller and the frusto-conical surface of said ring results in a downward component of force urging said ring downwardly in the course of travel of said traveller about said ring.
 2. Thread guiding device according to claim 1 wherein said ring has a given height, and said top portion of said traveller has an inner vertical spacing from said ring at least 15 percent greater than the given height of said ring.
 3. The thread guiding device according to claim 2 wherein a zone is formed in the spacing between said ring and the top portion of said traveller through which a thread being processed is passed.
 4. Thread guiding device according to claim 1 wherein said traveller has an arcuate upper portion extending upwardly from the uppermost engagement point thereof with said radially inner engagement surface of said ring, and said ring has an arcuate upper surface extending upwardly from said radially inner engagement surface thereof, said arcuate upper portion of said traveller having a radius of curvature substantially two or three times the radius of curvature of the arcuate upper surface of said ring.
 5. Thread guiding device according to claim 1 wherein the radially inner surface of said ring engageable by said traveller, is inclined between 4* to 14* to the vertical in the sense of increasing the diameter of said ring.
 6. Thread guiding device according to claim 1 wherein said ring has a total axial height of at most 10 mm.
 7. Thread guiding device according to claim 1 wherein said radially inner engagement surface of said ring merges with said upper surface of said ring in a curved surface portion having a radius of curvature that is one-fifth to one-fifteenth the total axial height of the ring.
 8. Thread guiding device according to claim 1 wherein said ring includes a radially outwardly extending holder portion, said holder portion having a height smaller than one-third the total axial height of the ring.
 9. Thread guiding device according to claim 1 wherein said traveller is a rod-shaped member formed at opposite ends thereof with a relatively larger and a relatively smaller hook-shaped portion respectively, facing toward one another and adapted to enclose sAid ring, said ring traveller having a maximum inner height of 12 mm, said relatively larger hook-shaped portion being curved in only one direction.
 10. Thread guiding device according to claim 9 wherein said relatively larger hook-shaped portion is substantially twice as long as said relatively smaller hook-shaped portion.
 11. Thread guiding device according to claim 9 wherein said relatively larger hook-shaped portion has an internal width that is at least 1.2 times the internal width of said relatively smaller hook-shaped portion.
 12. Thread guiding device according to claim 9 wherein the opposite ends of said rod-shaped member are spaced from one another a distance substantially equal to half the maximum inner height of the traveller.
 13. Thread guiding device according to claim 9 wherein at least the end of said relatively larger hook-shaped portion is outwardly directed. 